- ZnS and Cu doped ZnS nanoparticles were prepared using chemical co-precipitation method. The structural and optical properties were analyzed for different Cu2+ doping ratio (0.02M, 0.04M, 0.06M) using XRD, UV Visible spectroscopy, Photoluminescence spectra and FTIR study. The XRD pattern confirms Zinc blende structure with average crystallite size by 1.5 nm to 2.9 nm. The calculated band gap is in the ratio of 4.5 eV to 4.7 eV & band gap changes as the doping ratio of Cu2+ increases from 0.02M to 0.06M. Photoluminescence study of ZnS and Cu2+ doped ZnS exhibits blue and green emission peaks. FTIR spectral study confirms the presence of Cu2+ doped ZnS nanoparticles.